fix: Remove restriction to version <2 of urllib3 library (#851)

Author: arjankowski

setup.py

@@ -54,7 +54,7 @@ def main():
     base_dir = dirname(__file__)
     install_requires = [
         'attrs>=17.3.0',
-        'urllib3<2',
+        'urllib3',
         'requests>=2.4.3,<3',
         'requests-toolbelt>=0.4.0',
         'python-dateutil',  # To be removed after dropping Python 3.6